1 files changed, 11 insertions, 31 deletions

diff --git a/site/main.mjs b/site/main.mjs
index 703062d..877c0bc 100644
--- a/site/main.mjs
+++ b/site/main.mjs
@@ -91,6 +91,12 @@ function renderVars(vmvars) {
     });
 }
 
+function clamp(radius, x, y, width, height) {
+    const xx = Math.min(Math.max(radius, x), width-radius);
+    const yy = Math.min(Math.max(radius, y), height-radius);
+    return [xx, yy];
+}
+
 function renderRobo(ctx, x, y) {
     ctx.fillStyle = 'rgb(200 0 0)';
     ctx.beginPath();
@@ -111,9 +117,7 @@ function renderArena(robos, delta=0.0) {
         const [velx, vely] = [
             robo.speedx, robo.speedy
         ].map(x => timeScale * x);
-
-        const [_, x, y] = bounce(25, robo.heading, robo.x + velx, robo.y + vely, canvas.width, canvas.height);
-        //console.debug('bjc render robo', robo, velx, vely, x, y)
+        const [x, y] = clamp(25, robo.x + velx, robo.y + vely, canvas.width, canvas.height);
         renderRobo(ctx, x, y);
     });
 }
@@ -153,26 +157,6 @@ function loadForth(taintedPath) {
         });
 }
 
-function bounce(radius, heading, x, y, width, height) {
-    // todo: don't just clamp the x/y, instead calculate based on
-    // where the intersection with the wall is.
-    if (y < radius) {
-        // top wall
-        return [-1 * heading, x, radius];
-    } else if (y >= height-radius) {
-        // bottom wall
-        return [-1 * heading, x, height-radius];
-    } else if (x < radius) {
-        // left wall
-        return [heading - 180, radius, y];
-    } else if (x >= width-radius) {
-        // right wall
-        return [180 - heading, width-radius, y];
-    } else {
-        return [heading, x, y];
-    }
-}
-
 async function loaded() {
     const roboWorker = new Worker('robo.mjs', { type: 'module' });
     const robo = {
@@ -203,6 +187,7 @@ async function loaded() {
             }
             break;
         case 'tick':
+            console.debug('bjc tick', robo.heading, trans.vars.heading);
             const { word, offset } = trans.ip;
             document.querySelectorAll(IP_SELECTOR).forEach(e => e.classList.remove('ip'));
             const sel = selectorForIP(word, offset);
@@ -223,15 +208,10 @@ async function loaded() {
             ].map(x => robo.speed * x);
             robo.speedx = speedx;
             robo.speedy = speedy;
-            robo.x += speedx;
-            robo.y += speedy;
             const canvas = document.querySelector(CANVAS_SELECTOR);
-            const [newHeading, newx, newy] = bounce(25, trans.vars.heading, robo.x, robo.y, canvas.width, canvas.height);
-            if (newHeading != trans.vars.heading) {
-                roboWorker.postMessage({ kind: 'setHeading', heading: newHeading });
-                robo.x = newx;
-                robo.y = newy;
-            }
+            const [x, y] = clamp(25, robo.x + speedx, robo.y + speedy, canvas.width, canvas.height);
+            robo.x = x;
+            robo.y = y;
             renderArena([robo]);
             break;
         default: